title: The relationship between glucose metabolism, metabolic syndrome, and bone-specific alkaline phosphatase: a structural equation modeling approach.
abstract: BACKGROUND
  Serum alkaline phosphatase plays a role in vascular calcification. It is found in various tissues, whereas bone-specific alkaline phosphatase (BAP) more specifically reflects mineral metabolism. The relationship of serum alkaline phosphatase (total and bone-specific) with diabetes and metabolic syndrome (MetS), 2 major risk factors of vascular calcification, is largely unknown.
  
  
  OBJECTIVE
  We aimed to investigate the relationships between glucose metabolism, components of the MetS, and alkaline phosphatase.
  
  
  METHODS
  This was a cross-sectional study of a nationally representative sample of the U.S. population in 1999 through 2004.
  
  
  METHODS
  Participants were 3773 nondiabetic participants of the National Health and Nutrition Examination Survey 1999-2004.
  
  
  METHODS
  We measured serum BAP and total alkaline phosphatase.
  
  
  RESULTS
  In multivariable linear regression, updated homeostasis model assessment (HOMA2) for insulin resistance (β = 0.068), HOMA2 for β-cell function (β = 0.081), insulin (β = 0.065), mean arterial pressure (β = 0.15), and high-density lipoprotein (HDL)-cholesterol (β = 0.209) were positively associated with BAP, whereas HOMA2 for insulin sensitivity (β = -0.065) was negatively associated with BAP. On the other hand, only mean arterial pressure and HDL-cholesterol were significantly associated with total alkaline phosphatase. Moreover, a structural equation model revealed that hypertension, low HDL, and insulin resistance had significant direct effects on serum BAP levels, whereas obesity and inflammation might have indirect effects on serum BAP levels. The overall model showed very good fit to the data (comparative fit index = 0.995, root mean square error of approximation = 0.037, and standardized root mean square residual = 0.006).
  
  
  CONCLUSIONS
  Glucose metabolism and MetS are significantly related to serum BAP levels. How BAP mediates vascular calcification in diabetes and MetS warrants further studies.
authors.affiliation: Division of Clinical Pharmacology and Therapeutics, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Ching-Lung
authors.initials: CL
authors.lastname: Cheung
authors.forename: Kathryn C B
authors.initials: KC
authors.lastname: Tan
authors.forename: Karen S L
authors.initials: KS
authors.lastname: Lam
authors.forename: Bernard M Y
authors.initials: BM
authors.lastname: Cheung
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism*; D001842:Bone and Bones / Q000378:metabolism; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D024821:Metabolic Syndrome / Q000378:metabolism*; D008954:Models, Biological; D009749:Nutrition Surveys; D014481:United States
chemical_list: D001786:Blood Glucose; D007328:Insulin; D000469:Alkaline Phosphatase